21283391 has 8 divisors (see below), whose sum is σ = 22114944. Its totient is φ = 20460960.

The previous prime is 21283351. The next prime is 21283397. The reversal of 21283391 is 19338212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21283391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21283397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2681 + ... + 7053.

It is an arithmetic number, because the mean of its divisors is an integer number (2764368).

Almost surely, 2^21283391 is an apocalyptic number.

21283391 is a deficient number, since it is larger than the sum of its proper divisors (831553).

21283391 is a wasteful number, since it uses less digits than its factorization.

21283391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4561.

The product of its digits is 2592, while the sum is 29.

The square root of 21283391 is about 4613.3925694656. The cubic root of 21283391 is about 277.1279151336.

The spelling of 21283391 in words is "twenty-one million, two hundred eighty-three thousand, three hundred ninety-one".